Ultrasonic-assisted synthesis of highly stable RuPd bimetallic catalysts supported on MgAl-layered double hydroxide for N-ethylcarbazole hydrogenation

N-Ethylcarbazole (NEC), as a promising liquid organic hydrogen carrier (LOHC), can store and release hydrogen through a reversible catalytic hydrogenation and dehydrogenation reaction. In this paper, RuPd bimetallic nanocatalyst supported on MgAl-layered double hydroxide (RuPd/LDH) was prepared by ultrasonic-assisted reduction method, and its catalytic performance in NEC hydrogenation was also studied. Under the action of ultrasound, hydroxyl groups (-OH) on the surface of LDH support dissociated into highly reductive hydrogen radicals for the reduction of Ru3+ and Pd2+ to Ru-0 and Pd-0. For the 4Ru1Pd/LDH-(300-1) catalyst prepared under ultrasonic conditions of 25 kHz, 300 W, and 1 h, the average size of the metal nanoparticles was only 1.23 nm, which indicated that Ru, Pd, and RuPd NPs were highly dispersed on the support. The strong electronic effects between Ru and Pd improved its catalytic performance in NEC hydrogenation. With m((Ru+Pd))/m((NEC)) = 0.2wt%, pressure of 6 MPa, and temperature of 120 degrees C, the selectivity of dodecahydro-N-ethylcarbazole (12H-NEC) was 98.07%, and the capacity and percentage of hydrogen storage were 5.75wt% and 99.3%, respectively. After the catalyst was recycled 8 times, the percentage of hydrogen storage still reached 98.9%, showing higher stability. The preparation method is simple and environmentally friendly, providing an idea for the preparation of ultrafine bimetallic catalysts with high catalytic activity and stability.

Automated summary

This paper studied the catalytic performance of RuPd bimetallic nanocatalyst supported on MgAl-layered double hydroxide in the hydrogenation of N-Ethylcarbazole (NEC). The catalyst, prepared by ultrasonic-assisted reduction method, showed highly dispersed nanoparticles and improved catalytic performance due to the strong electronic effects between Ru and Pd. The catalyst exhibited high selectivity, hydrogen storage capacity, and stability under specific conditions. The study provides a simple and environmentally friendly method for preparing ultrafine bimetallic catalysts with high catalytic activity and stability.